1. Field of the Invention
This invention relates to a casing having a bending wall surface (corner portion) provided with a porous elastic member (insulator) for absorbing noise and insulating heat on an inner wall thereof, and is effectively employed for an air conditioning case of an air conditioning apparatus for a vehicle, for example.
2. Description of Related Art
Conventionally, an insulator is disposed on an inner wall of a casing, as described below.
That is, a plane insulator sheet is formed along a shape of a concave portion by a vacuum forming method (refer to JP-A-3-256726), and then a worker manually cuts and removes (trims) unnecessary portions of an outer edge of the insulator. After the worker paints an adhesive on an inner wall of the casing, and the trimmed insulator is manually affixed onto the inner wall of the casing.
When the insulator is affixed onto the inner wall of the casing, if a work for pressing (contacting closely) a whole surface of the insulator onto the inner surface is insufficient, there occurs a defective adhesion such as a void space or peeling of the insulator. Therefore, as described above, if the insulator is manually affixed onto the inner wall, because a defective adhesion due to an insufficient pressing work may be caused, a yield of the casing may deteriorate, and a manufacturing cost of the casing may be increased.
To eliminate the insufficient pressing work, the inventors of the present invention have tried a method for fixing the insulator when the resinous casing is molded, as disclosed in U.S. Pat. No. 4,994,226. As a result, as shown in FIG. 9C, there has been discovered a defective "reversing" in which at a corner portion an insulator 20 is exposed to a side of an outer wall of a casing 10. In FIG. 9C, the numerals 100 and 101 are dies for molding a resinous casing.